Manometric and Electrode-Probe Determination of CO2 in Fish Flesh

1982 ◽  
Vol 45 (10) ◽  
pp. 932-934 ◽  
Author(s):  
JIM W. CONRAD ◽  
GLENN C. ROBERTS ◽  
HAROLD J. BARNETT
Keyword(s):  
Mean Difference ◽  
Fish Products ◽  
Probe Technique ◽  
Fish Flesh ◽  
Ion Probe ◽  
Low Concentrations ◽  
Manometric Method ◽  
High Concentrations ◽  
Manometric Technique

A rapid electrometric method for determining endogenous and added CO2 in fish products was studied using an Orion CO2 probe and Orion ionalyzer model #801. Analytical results were compared to those using the standard Warburg manometric technique. Comparisons showed a ± 20.8% mean difference for low concentrations of CO2 (<350 ppm) and a ± 10.7% mean difference for high concentrations of CO2 (>800 ppm). The probe technique was found to be easier to use and required less time for operating and cleanup procedures than the manometric method. Based on recovery studies, the specific ion probe was more accurate at all levels of CO2 evaluated than the manometric device.

scholarly journals The Double Face of Ketamine—The Possibility of Its Identification in Blood and Beverages

Molecules ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 813
Author(s):  
Magdalena Świądro ◽  
Paweł Stelmaszczyk ◽  
Irena Lenart ◽  
Renata Wietecha-Posłuszny
Keyword(s):  
Date Rape ◽  
Signal To Noise Ratio ◽  
High Sensitivity ◽  
Heroin Addiction ◽  
Assisted Extraction ◽  
Low Concentrations ◽  
High Concentrations ◽  
Rosé Wine ◽  
Tof Ms

The purpose of this study was to develop and validate a high-sensitivity methodology for identifying one of the most used drugs—ketamine. Ketamine is used medicinally to treat depression, alcoholism, and heroin addiction. Moreover, ketamine is the main ingredient used in so-called “date-rape” pills (DRP). This study presents a novel methodology for the simultaneous determination of ketamine based on the Dried Blood Spot (DBS) method, in combination with capillary electrophoresis coupled with a mass spectrometer (CE-TOF-MS). Then, 6-mm circles were punched out from DBS collected on Whatman DMPK-C paper and extracted using microwave-assisted extraction (MAE). The assay was linear in the range of 25–300 ng/mL. Values of limits of detection (LOD = 6.0 ng/mL) and quantification (LOQ = 19.8 ng/mL) were determined based on the signal to noise ratio. Intra-day precision at each determined concentration level was in the range of 6.1–11.1%, and inter-day between 7.9–13.1%. The obtained precision was under 15.0% (for medium and high concentrations) and lower than 20.0% (for low concentrations), which are in accordance with acceptance criteria. Therefore, the DBS/MAE/CE-TOF-MS method was successfully checked for analysis of ketamine in matrices other than blood, i.e., rose wine and orange juice. Moreover, it is possible to identify ketamine in the presence of flunitrazepam, which is the other most popular ingredient used in DRP. Based on this information, the selectivity of the proposed methodology for identifying ketamine in the presence of other components of rape pills was checked.

Inorganic polysulfides’ quantitation by methyl iodide derivatization: dimethylpolysulfide formation potential

2004 ◽  
Vol 49 (9) ◽  
pp. 179-184 ◽  
Author(s):  
A. Goifman ◽  
D. Ryzkov ◽  
J. Gun ◽  
A. Kamyshny ◽  
A.D. Modestov ◽  
...  
Keyword(s):  
Methyl Iodide ◽  
Direct Determination ◽  
Solubility Limit ◽  
Environmental Significance ◽  
Valuable Alternative ◽  
Natural Systems ◽  
Low Concentrations ◽  
Inorganic Polysulfides ◽  
High Concentrations

Inorganic polysulfides are important intermediates in the formation of dimethylpolysulfides and possibly other volatile sulfur compounds of environmental significance. Currently, direct determination of these ions in the concentration range of natural systems is practically impossible, particularly under oxic conditions. Polysulfide quantification by derivatization with methyl iodide or d6-methyl iodide is emerging as a valuable alternative method for studies of polysulfide formation in natural systems. This manuscript presents detailed studies aimed at the evaluation of this method. We determined the conversion of the inorganic polysulfides to dimethylpolysulfides by methylation with methyl iodide. Close to 100 per cent of the molar concentration of polysulfide salts were converted to organic polysulfides for very low concentrations of dissolved polysulfide solutions, but only a small recovery was obtained for high concentrations of polysulfide precursors or when the solubility limit was exceeded. The recovery of polysulfides based on the calculated dissolved polysulfide concentration exceeds 1,000 per cent for very low dissolved concentrations of polysulfides. This unexpected dependence is attributed to continuous inorganic polysulfide formation from hydrogen sulfide and sulfur precipitate concurrent with, and in fact driven by, the methylation process.

scholarly journals Determination of Zinc-Based Additives in Lubricating Oils by Flow-Injection Analysis with Flame-AAS Detection Exploiting Injection with a Computer-Controlled Syringe

2005 ◽  
Vol 2005 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Gustavo Pignalosa ◽  
Moisés Knochen ◽  
Noel Cabrera
Keyword(s):  
Flow Injection ◽  
Computer Control ◽  
Injection System ◽  
Mean Values ◽  
Lubricating Oils ◽  
Low Concentrations ◽  
Flow Injection System ◽  
High Concentrations ◽  
Zinc Levels

A flow-injection system is proposed for the determination of metal-based additives in lubricating oils. The system, operating under computer control uses a motorised syringe for measuring and injecting the oil sample (200μL) in a kerosene stream, where it is dispersed by means of a packed mixing reactor and carried to an atomic absorption spectrometer which is used as detector. Zinc was used as model analyte. Two different systems were evaluated, one for low concentrations (range 0–10 ppm) and the second capable of providing higher dilution rates for high concentrations (range 0.02%–0.2% w/w). The sampling frequency was about 30 samples/h. Calibration curves fitted a second-degree regression model (r2= 0.996). Commercial samples with high and low zinc levels were analysed by the proposed method and the results were compared with those obtained with the standard ASTM method. Thettest for mean values showed no significant differences at the 95% confidence level. Precision (RSD%) was better than 5% (2% typical) for the high concentrations system. The carryover between successive injections was found to be negligible.

Application of Electron Microprobe Age Mapping and Dating of Monazite

2000 ◽  
Vol 6 (S2) ◽  
pp. 406-407
Author(s):  
M. L. Williams ◽  
M. J. Jercinovic
Keyword(s):  
Electron Microprobe ◽  
Age Determination ◽  
Thin Sections ◽  
Geologic Materials ◽  
Mineral Growth ◽  
Ion Probe ◽  
Accessory Phase ◽  
High Concentrations ◽  
Individual Grains

High resolution X-ray mapping and dating of monazite (Th, REE-phosphate) using the electron microprobe is an exceptionally powerful technique for structural, metamorphic, and tectonic analysis in geology. Age determination of geologic materials has been conventionally accomplished by mass spectrometry-based analysis of radioisotopic ratios in minerals from hand-picked mineral separates, careful sampling of individual grains out of petrographic thin sections, or by detailed ion probe analysis. Recently, use of the electron microprobe for dating purposes has been attempted. In principal, the concentrations of Th, U and Pb uniquely define the age if non-radiogenic Pb is either not initially present or can be subtracted from the total Pb. Monazite contains high concentrations of Th and U and does not appear to incorporate significant non-radiogenic Pb during mineral growth. Furthermore, monazite is a ubiquitous accessory phase in many metamorphic and igneous rocks, making it ideal for microprobe dating.

scholarly journals Association of polymorphism rs7903146 gene TCF7L2 with low concentrations of autoantibodies in latent autoimmune diabetes of adults (LADA)

2016 ◽  
Vol 19 (3) ◽  
pp. 199-203 ◽  
Author(s):  
Iuliia V. Silko ◽  
Tatiana V. Nikonova ◽  
Olga N. Ivanova ◽  
Svetlana M. Stepanova ◽  
Marina V. Shestakova ◽  
...  
Keyword(s):  
Odds Ratio ◽  
Autoimmune Diabetes ◽  
Polymorphic Marker ◽  
Healthy Individuals ◽  
Tcf7l2 Gene ◽  
Latent Autoimmune Diabetes ◽  
Low Concentrations ◽  
High Concentrations

Aim. To determine the frequencies of alleles and genotypes of polymorphic marker rs7903146 of the TCF7L2 gene in latent autoimmune diabetes in adults (LADA) and healthy individuals. The aims of the study were also to compare the distribution of alleles and genotypes and to explore the association with the development of LADA.Materials and methods. A total of 96 patients (46 females and 50 males) with LADA and 201 healthy individuals were examined. A quantitative determination of autoantibodies GADA, ICA, IA-2A and ZnT8 in the serum of LADA patients was performed. All patients underwent genotyping of rs7903146 of the TCF7L2 genes.Results. There was an increased frequency of the T allele and genotype T+ of marker rs7903146 of the TCF7L2 gene in patients with LADA with low concentrations of autoantibodies compared to a group of patients with high concentrations and with controls. We observed significant associations of the T allele and genotype T+ with LADA in patients with low concentrations of autoantibodies [p = 0.02; odds ratio (OR) = 1.85; 95% confidence interval (CI) = 1.10–3.13 and p = 0.04; OR = 2.14; 95% CI = 1.01–4.53 for the T allele and genotype T+, respectively).Conclusion. The results of the study suggest that LADA patients with low concentrations of autoantibodies have a genetically pre-determined similarity with patients with type 2 diabetes.

scholarly journals Atomic Absorption Spectrometric Determination of Chromium, Copper, Lead, Mercury, and Zinc in Sediments Collected in Bayou d'Inde, Southwestern Louisiana

2002 ◽  
Vol 85 (1) ◽  
pp. 225-232 ◽  
Author(s):  
Carey Hardaway ◽  
Kermit Gauthreaux ◽  
Joseph Sneddon ◽  
James N Beck
Keyword(s):  
Trace Metals ◽  
Atomic Absorption ◽  
Sediment Cores ◽  
Sedimentation Rates ◽  
Low Concentrations ◽  
High Concentrations ◽  
Atomic Absorption Spectrometric ◽  
Copper Lead

Abstract The concentrations of the metals chromium (Cr), copper (Cu), lead (Pb), mercury (Hg), and zinc (Zn) were determined in sediment cores taken from Bayou d'Inde in southwestern Louisiana. Previous studies had reported elevated concentrations of these trace metals in sediments along this waterway. The current study, conducted more than a decade later, was designed to determine if these metals had migrated from the areas of highest concentrations. Concentrations as high as 400 mg/kg for Cr, 1100 mg/kg for Cu, 10 mg/kg for Hg, and 600 mg/kg for Pb and Zn were found. Areas of high concentrations of metals were isolated within a distance of about 1 km from the most highly contaminated areas in the bayou. Low concentrations of metals were found at the mouth of the bayou. Estimated sedimentation rates of 0.67–1.2 cm/yr were based on the burial of the sediments originally studied. The concentrations of the metals studied remained high and were also highly localized, both spatially and temporally.

Effect of low fibrinogen concentrations on the rheology of human blood in vitro

1979 ◽  
Vol 236 (3) ◽  
pp. H447-H450
Author(s):  
W. Blattler ◽  
P. W. Straub ◽  
C. Jeanneret ◽  
G. S. Horak
Keyword(s):  
Human Blood ◽  
Cell Aggregation ◽  
Fibrinogen Concentration ◽  
Shear Rates ◽  
Red Blood Cell Aggregation ◽  
Low Concentrations ◽  
Normal Human ◽  
High Concentrations

The influence of low concentrations of fibrinogen on the rheology of normal human blood was investigated with an instrument that permitted simultaneous determination of viscosity and the state of red blood cell aggregation and deformation. Fibrinogen, in concentrations of 9-82 mg/100 ml, decreased blood viscosity at all shear rates below the value obtained with red blood cells suspended in serum. At concentrations above 116 mg/100 ml viscosity was increased. Aggregate formation increased progressively as the fibrinogen concentration increased, necessitating higher dispersing shear rates. The deformation and alignment of the red cells, occurring at a shear rate of 230 s-1, was facilitated by low concentrations. The effect of fibrinogen on low-shear viscosity is explained by the formation of different kinds of aggregates. At low concentrations, the aggregates consist of only few cells forming spherelike particles displaying hemodynamic properties better than those of the single discoid cells. At normal or high concentrations big rodlike aggregates occur and increase resistance to flow.

Determination of urinary norepinephrine and epinephrine by liquid chromatography with fluorescence detection and pre-column derivatization

1990 ◽  
Vol 36 (5) ◽  
pp. 732-736 ◽  
Author(s):  
P Moleman ◽  
J van Dijk
Keyword(s):  
Liquid Chromatography ◽  
Present Method ◽  
High Performance ◽  
Reversed Phase ◽  
Fluorescence Derivatization ◽  
Specificity And Sensitivity ◽  
Low Concentrations ◽  
High Concentrations ◽  
Phase Column

Abstract We assayed norepinephrine and epinephrine by utilizing solvent extraction, fluorescence derivatization, and "high-performance" liquid chromatography. A 100-microL aliquot of urine was extracted twice according to Smedes et al. (J Chromatogr 1982;231:25-39) and subsequently incubated with 1,2-diphenylethylenediamine. A 100-microL aliquot of the resulting mixture was injected into a reversed-phase column, and norepinephrine and epinephrine were detected fluorometrically. The within-day CV was 3.0-4.0% and the between-day CV 3.4-7.1% for normal and high concentrations of both analytes. At low concentrations (15-40 nmol/L) these CVs were 4.2-6.8% and 6.8-9.2%, respectively. The detection limit of the assay was less than 0.4 nmol/L for each analyte. We discuss the critical steps for extraction, derivatization, and chromatography. The present method combines the qualities of high precision, specificity, and sensitivity.

THE DETERMINATION OF STEROIDS IN CYST FLUID FROM HUMAN POLYCYSTIC OVARIES

1963 ◽  
Vol 27 (2) ◽  
pp. 225-240 ◽  
Author(s):  
ELEONORA P. GIORGI
Keyword(s):  
Paper Chromatography ◽  
Cyst Fluid ◽  
Adsorption Chromatography ◽  
Polycystic Ovaries ◽  
Low Concentrations ◽  
Definite Pattern ◽  
High Concentrations

SUMMARY A micro-method has been developed for the determination of Δ4-3-ketosteroids and Δ5-3β-hydroxysteroids, oestradiol-17β, oestrone and oestriol in small volumes of cyst fluid. The method consists of separation of the neutral and phenolic fractions by solvent partition; fractionation of the neutral steroids by partition and paper chromatography and of the three oestrogens by adsorption chromatography after methylation. This technique has been applied to cyst fluid from the ovaries of twenty-one patients, twelve with the Stein—Leventhal syndrome, and nine with other gynaecological disorders. In the patients with the Stein—Leventhal syndrome the steroid concentrations in cyst fluid showed a definite pattern characterized by high concentrations of Δ4-androstenedione, low concentrations of progesterone and 17α-hydroxyprogesterone, and small amounts or undetectable oestrogens. In cyst fluid from the ovaries of the nine control patients there were, in general, lower concentrations of Δ4-androstenedione and significant amounts of oestradiol-17β. High concentrations of progesterone and oestrogens were found in the cyst fluid of patients with menorrhagia and endometriosis.

Determination of histamine in fish and fish products: validation of photometric method

2021 ◽  
pp. 58-61
Author(s):  
O.O. Kharchenko ◽  
◽  
M.P. Hulich ◽  
O.V. Yashchenko ◽  
I.Ye. Moiseienko ◽  
...  
Keyword(s):  
Quality Control ◽  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
High Performance ◽  
Photometric Method ◽  
Inexpensive Method ◽  
Total Uncertainty ◽  
Fish Products ◽  
High Concentrations

Topicality: The content of histamine in high concentrations causes a number of diseases that even lead to death, it is one of the indicators that characterizes the safety of fish and fish products. Therefore, the choice or development of a simple and inexpensive method for the determination of histamine content in fish and fish products is relevant. Objective: We confirmed the effectiveness of photometric method for the determination of histamine in fish and fish products by obtaining and analyzing validation characteristics. Results: Based on the results of validation, it has been substantiated and experimentally proved that the photometric method of quantitative determination of histamine can be correctly reproduced and is suitable for the quality control of measurements. The most acceptable results were obtained for histamine concentrations in the range from 50.0 ± 0.1 to 200.0 ± 0.5 mg/kg. The lower histamine concentrations are characterized by a higher percentage of total uncertainty, although it is also within acceptable values. Conclusions: Evaluation of the obtained validation characteristics indicates that this technique can be used to quantify the content of histamine in fish and fish products and is not inferior in accuracy and correctness to the method of high performance liquid chromatography.

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